1. Field of the Invention
The present invention relates to syringes and more particularly concerns syringe barrels having features to improve graphics visualization.
2. Description of Related Information
Generally speaking, a hypodermic syringe consists of a cylindrical barrel, most commonly made of thermoplastic material or glass, having a distal end connected to a sharpened needle cannula or adapted to be connected to a hypodermic needle assembly and a proximal open end adapted to receive a stopper and plunger rod assembly. One of the purposes of the stopper is to provide a relatively fluid tight seal between itself and the syringe barrel so that movement of the stopper along the barrel will cause liquid to be drawn into or forced out of the syringe through the distal end. The stopper is moved along the syringe barrel by applying axial force to a rigid plunger rod which is connected to the stopper and is sufficiently long to be accessible outside of the barrel.
Syringes usually contain indicia such as volume measuring indicia on the side of the barrel to indicate the volume of liquid contained within the syringe. It is desirable for convenient use and to prevent medical error to provide volume measuring indicia which are clear and easy to read by the person filling the syringe and/or administrating medication using the syringe. The need for easy to read graphics on a syringe barrel is especially acute with respect to diabetics who, after many years of affliction, suffer various side effects of this disease and its treatment such as failing vision. Diabetics also are believed to suffer from temporary periods of blurred vision. To this end the art teaches devices for attachment to syringes for the purpose of magnifying the volume measuring indicia. Such a device is taught in U.S. Pat. No. 2,586,581 to Tschischeck. Tschischeck teaches a magnifying attachment for syringes and similar instruments which contains a pair of parallel spaced elongated wire loops which are embedded in the bottom wall of an elongated section which performs the magnification function. The loops are designed to engage the syringe by snap on movement. The magnifying attachment stays with the syringe until it is removed for various reasons such as for use on another syringe.
Additional teachings in the prior art address improving the readability of volume measuring indicia by providing higher quality volume measuring indicia on the syringe barrel. In particular, a corona discharge treatment of the surface of various formed plastic articles such as syringe barrels will improve the compatibility of the surface with printing inks to provide higher quality printed indicia. Such a method is taught by Macy in U.S. Pat. No. 4,724,508.
Many hypodermic syringe barrels are made of glass or transparent plastic having graphics such as volume measuring indicia along their side walls. Improved quality of volume measuring indicia will not be enough if the transparent syringe barrel is held near a background which is similar in color and/or shade to the graphics. Under these conditions the graphics may be difficult to observe. Also, separate attachable magnifying devices will not overcome problems in this area.
Although the art has provided teachings directed toward improving the readability of indicia such as volume measuring indicia on a syringe barrel wall through the use of separate devices and improved printing there is still a need for a simple, straight forward, reliable, easily fabricated syringe barrel having means to improve the readability of the volume measuring indicia without the use of separate additional elements, devices or holders. There is also need to improve readability of the volume measuring indicia when the syringe is used in the background which is a similar color or shade to the volume measuring indicia.